某工业废渣堆放场地重金属污染特征与健康风险评估

以某工业废渣堆积场为例,探讨了该场地废渣、土壤和地下水中重金属污染特征,着重评估了重金属污染对人体的致癌风险和危害商值。结果表明:1)场地废渣中8种重金属(As、Cu、Ni、Zn、Cd、Pb、Cr、Hg)均有不同程度超标,其中As污染范围最大(超标率达91%),Cr存在高污染集中区,土壤中Cu、Ni、Zn和Cd浓度超出当地背景值,地下水中As和Ni也存在超标现象;2)废渣和土壤中的As、Ni和Cr三种重金属的致癌风险水平均超过了致癌风险可接受水平(1.0×10^-6),其中Cr的致癌风险最高,高达5.3×10^-3,相同金属元素废渣的致癌风险值大于其在土壤中的风险值;3)废渣中As、Cr和Cd的危害商值大于其可接受水平(1),其中Cr的危害商值最大(高达7.5),土壤中重金属的危害商值基本在可接受范围(除As外);4)三种暴露途径按贡献率从大到小依次为:经口摄入>吸入土壤颗粒物>皮肤接触。

Pollution characteristics and health risk assessment of heavy metal in a waste residue disposal site

Taking an industrial waste dump plate as the example, the pollution characteristics of heavy metals in the waste residue, soil and groundwater were discussed, and the carcinogenic risk and harm quotient of heavy metal pollution to human body were evaluated emphatically in this paper. Results show that: 1) 8 kinds of heavy metals (As, Cu, Ni, Zn, Cd, Pb, Cr and Hg) in the slag exceed certain limits to some extent, with the maximum value of As (up to 91% in the rate of exceeding standard) and a highly concentrated contaminated area for Cr. Contents of Cu, Ni, zinc and Cd in the soil are greater than local background values. As and Ni in the groundwater also exceed standards. 2) The carcinogenic risk levels of As, Ni and Cr in waste residues and soils all exceed the acceptable level of carcinogenic risk (1.0×10-6), with the highest carcinogenic risk of Cr, up to 5.3×10-3. For the same heavy metal the carcinogenic risk values in waste residues are greater than in soils. 3) The hazard quotients of As, Cr and Cd in the waste residues are greater than the acceptable level (1), with the highest hazard quotients of Cr (up to 7.5), while the hazard quotients of all heavy metals (except As) in the soils are basically lower than the acceptable level. 4) The three exposure pathways are listed in descending order according to their contribution rates as follows: oral intake > inhaled soil particles > through skin contact.